N-.beta.-Alanyl-2-mercaptoethylamine (hereinafter referrs to as .beta.-aletheine) is well known as the constituent of pantetheine and pantethine. Pantetheine or pantethine, when administered to human, is rapidly converted into coenzyme-A which plays an important role in lipo-metabolism. .beta.-Aletheine forms the terminal structure of coenzyme-A, but useful pharmacological effects thereof has not been known. The utilization of .beta.-aletheine, as an intermediate for preparing pantetheine or pantethine is only reported (Journal of American Chemical Society, 75, 1290 (1953), ibid., 75, 1695 (1953), Journal of Chemical Society, 1952, 800). As the result of our precise examination on the pharmacological effects of .beta.-aletheine, we found that .beta.-aletheine itself shows an excellent suppressive effect on liver damage. We continuously studied the known aletheine derivatives and found that N,S-diacetyl derivative and N-benzyloxycarbonyl derivative have a superior effect on liver-damage.
On the other hand, through further studies on for .beta.-aletheine we prepared novel .beta.-aletheine derivatives and examined their pharmacological effects and found that they also have superior effect on liver damage.